Re: Speed of PrimaryKey vs Index

On 03-Mär-99 21:11:19 Stan wrote:

>I am using Oracle with Delphi (using a TTable and TDBGrid - this is not
>necessary to know). I am using a grid component to display my data.
>When the data is sorted on the primary key, it navigates very quickly.
>However, if I switch the sort order to the Index key, it moves very
>slowly.

This seems not to be Oracle's fault. As far as I know do TTable components first investigate the Oracle table in order to find out wehich indexes are there and what the indexed columns are. When you open the TTable, it generates the SQL sent to Oracle. Maybe it generates some strange SQLs that perform badly. You should try setting sql_trace=true in order to find out the exact SQL that is sent to Oracle. If you have Delphi C/S you also can use SQLMonitor to find out.
Then you could do explain plan to find out the execution plan for these SQLs. To have better performance, you should optimize these SQLs and use them in TQuery components. These ones normally perform much better than tables when used with an Oracle database.

>Stan.

Hope that helps,
Lothar

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Lothar Armbrüster       | lothar.armbruester_at_rheingau.netsurf.de
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